The present invention relates to a method for processing a silver halide photographic light-sensitive material (hereinafter sometimes referred to as a photographic material or a light-sensitive material) and, particularly, to a fixing solution and a fixing processing method.
A silver halide black-and-white photographic material is processed, after being subjected to an exposure, by steps of developing, fixing, washing and drying. In general, a hardening fixing solution containing a water-soluble aluminum salt is used for a hardening processing in the fixing step to shorten the drying time and facilitate a passage of the photographic material in an automatic processor.
However, although the hardening fixing solution containing a water-soluble aluminum salt can prevent generation of a hardly soluble aluminum salt by reducing the pH thereof, a problem of sulfurization arises when it is preserved as a concentrated solution because it contains a thiosulfate as a fixing agent. On the other hand, although the stability of the fixing agent is improved and dyes in the photographic material during processing can be easily dissolved and removed by raising the pH of the hardening fixing solution, the generation of the hardly soluble aluminum salt is accelerated by raising the pH. According, it is preferable that a hardening fixing solution of one ingredient type has a pH of from 4.6 to 4.9. However, the generation of the hardly soluble aluminum salt cannot be completely inhibited if the pH is adjusted to such a range, and particularly the concentrated solution cannot be easily prepared. In general, a boron compound is used to solve these problems in a large amount. The boron compound is carried over to a washing step because the fixing solution is carried over thereto along with the photographic material during processing, and as a result, it is released in environment with a waste water. In the meantime, the environmental preservation has become a world-wide problem in recent years, and it has been strongly demanded in photographic processing to reduce the boron compound contained in a waste water.
To cope with this problem, a method processed by a fixing solution which does not substantially contain a boron compound has been proposed. In this method, a fixing solution is divided into two ingredients, one is an acidic solution containing a water-soluble aluminum salt and the other is a solution containing a thiosulfate and having a pH of from 4.6 to 5.0 or more, and the ingredients are mixed when used. However, it is important and necessary to supply these solutions in one ingredient from the point of conveniences of the supply to users and the usage thereof and further from the production costs.
Regarding this point, it has already been known that an organic acid is effective to prevent the generation of a hardly soluble aluminum compound in the solution used. For example, use of an organic acid such as a gluconic acid, a glycolic acid or a maleic acid instead of a boron compound is disclosed in Research Disclosure, No. 18728. In addition to this, examples of replacing a part or the whole of a boron compound with an organic acid are disclosed in Research Disclosure, No. 16768 and JP-A-63-284546 (the term xe2x80x9cJP-Axe2x80x9d as used herein means a xe2x80x9cpublished unexamined Japanese patent applicationxe2x80x9d), but they do not disclose the stability of the solutions which are concentrated. However, when these solutions are supplied to users, it is essential for them to be in the form of concentrated solutions from the point of convenience of the transportation and the storage, and from the viewpoint of reducing the waste package materials, and the storage stability of them is an indispensable characteristic. However, the use of an organic acid in concentrated solution components of one ingredient type hardening fixing solution has not yet been known because a sufficient stability cannot be obtained such that depositions of components arise due to high concentrations of salts of concentrated solution components.
The stabilization of an aluminum salt by an organic acid can be explained by the complex formation thereof but, as described above, components of a concentrated solution of high concentration of salts are liable to be deposited, therefore, it is extremely difficult to apply using methods of organic acids in the known form of solutions used to a concentrated solution. Therefore, whether the stability of one ingredient type concentrated hardening fixing solution can be obtained or not by the use of an organic acid cannot be known at all from the use examples in the form of solutions used.
An object of the present invention is to provide a concentrated hardening fixing solution of one ingredient type (hereinafter sometimes referred to as xe2x80x9cone ingredient type concentrated fixing solutionxe2x80x9d) which does not substantially contain a boron compound that pollutes the environment and which is excellent in aging stability.
Another object of the present invention is to provide a method for processing a photographic material by using the fixing solution.
These and other objects of the present invention have been achieved by a concentrated fixing solution of one ingredient type which comprises at least a thiosulfate, a water-soluble aluminum salt, and a compound having an absorbance of from 0.25 to 1.15, and does not substantially contain a boron compound, wherein the absorbance is measured by an absorptiometer of ultraviolet light/visible light in a solution having a pH of 4.85 and containing a buffer solution of 1.55 mol/liter of an acetic acid/sodium acetate, 2.5xc3x9710xe2x88x924 mol/liter of Al3+, 2.5xc3x9710xe2x88x925 mol/liter of the following compound A, and 5xc3x9710xe2x88x923 mol/liter of a compound for evaluation: 
Further, these and other objects of the present invention have been achieved by a method of processing a silver halide photographic material, which comprises the steps of developing an exposed silver halide photographic material, and then processing the developed photographic material with a fixing solution obtained by diluting the above-described concentrated fixing solution to a prescribed concentration.
The present invention is described in detail below.
In the present invention, the phrase xe2x80x9cwhich does not substantially contain a boron compoundxe2x80x9d means that the concentration of the boron compound is 0.04 mol/liter in the fixing solution.
A colorimetric method used in the present invention is a method indirectly representing the stability of a complex formed by an organic acid to be evaluated and Al3+ by measuring the absorbance of the complex formed by Al3+ which is not masked by the organic acid and compound A. That is, the smaller the absorbance, the larger is the masking ability of Al3+.
Practically, a solution having a pH of 4.85 and containing a buffer solution of acetic acid/sodium acetate (1.55 mol/liter in terms of acetic acid), Al3+ (2.5xc3x9710xe2x88x924 mol/liter), compound A (2.5xc3x9710xe2x88x925 mol/liter), and a compound to be evaluated (5xc3x9710xe2x88x923 mol/liter) is prepared, and the absorbance of the solution is measured by an absorptiometer of ultraviolet light/visible light at a wavelength of from 500 to 600 nm. The absorbance value of boric acid conventionally used is 1.14 when measured by this method, on the other hand, those of 5-sulfosalicylic acid, iminodiacetic acid, sodium gluconate, malic acid, and tartaric acid are 0.54, 0.90, 0.93, 0.28 and 0.34, respectively.
When a compound having an absorbance value of less than 0.25 by this method is used alone, a sufficient hardening effect cannot be obtained in processing of a photographic material because its masking ability of Al3+ is too strong. On the other hand, when a compound having an absorbance value exceeding 1.15 is used alone, since its masking ability of Al3+ is too weak, an aluminum compound is deposited during the preparation of a concentrated solution or the storage thereof, or an aluminum hydroxide is deposited in a fixing tank during processing using an automatic processor. On the other hand, a compound having an absorbance value of from 0.25 to 1.15, preferably from 0.4 to 1.12, by this colorimetric method has an appropriate masking ability of Al3+ and a sufficient hardening ability, therefore, a sufficient stability can be maintained during the preparation of a concentrated solution, the storage thereof, and the time when the solution is used.
Preferable examples of the compound of the present invention include a gluconic acid and derivatives and salts thereof, an iminodiacetic acid and derivatives and salts thereof, a 5-sulfosalicylic acid and derivatives and salts thereof such as 4-sulfosalicylic acid, a glucoheptanic acid and derivatives and salts thereof. The gluconic acid may be an anhydride having a lactonized ring such as glucono-xcex94-lactone. The gluconic acid, the iminodiacetic acid, respective alkali metal salts thereof, and respective ammonium salts thereof are more preferred. These compounds are used in an amount of from 0.01 to 0.45 mol/liter, preferably from 0.015 to 0.3 mol/liter, in one ingredient type concentrated fixing solution which does not substantially not contain a boron compound.
They may be used alone, or two or more kinds of them may be used in combination. Further, they are preferably used in the present invention in combination with one or more compounds, such as organic acids (e.g., malic acid, tartaric acid, citric acid, succinic acid, oxalic acid, maleic acid, glycolic acid, benzoic acid, salicylic acid, Tiron (disodium salt of 1,2-dihydroxybenzene-3,5-disulfonic acid), ascorbic acid, glutaric acid, adipic acid), amino acids (e.g., aspartic acid, glycine, cysteine), aminopolycarboxylic acids (e.g., ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, 1,3-propanediaminetetraacetic acid, nitrilotriacetic acid) and saccharides (e.g., glucose, maltose, cellulose).
The fixing agent of the fixing solution in the present invention are not particularly limited, but ammonium thiosulfate and sodium thiosulfate are preferably used. The amount used of the fixing agent may be varied according to the object and that in the concentrated solution is generally from 0.8 to 6 mol/liter.
The fixing solution of the present invention contains a water-soluble aluminum salt having an effect as a hardening agent, such as aluminum chloride, aluminum sulfate, potassium alum, or aluminum ammonium sulfate. They are preferably contained in an amount of from 0.01 to 0.3 mol/liter, preferably 0.04 to 0.2 mol/liter, in terms of an aluminum ion concentration in the concentrated solution.
The pH of the concentrated fixing solution of the present invention is 4.0 or more and preferably from 4.6 to 5.5.
The fixing solution can include, if necessary, a preservative (e.g., sulfite, bisulfite), a pH buffer (e.g., acetic acid, sodium carbonate, sodium hydrogencarbonate, phosphate, phosphite), a pH adjustor (e.g., sodium hydroxide, ammonia, sulfuric acid), a chelating agent having a water softening ability, compounds disclosed in JP-A-62-78551, a surfactant, a wetting agent, and a fixing accelerator. Specific examples of the surfactant include anionic surfactants such as a sulfide and a sulfone oxide, polyethylene surfactants, and amphoteric surfactants disclosed in JP-A-57-6840, and known defoaming agents can also be used. Specific examples of the wetting agent include alkanolamines and alkylene glycols. Specific examples of the fixing accelerator include alkyl- or aryl-substituted thiosulfonic acids and the salts thereof, thiourea derivatives disclosed in JP-B-45-35754, JP-B-58-122535 and JP-B-58-122536 (the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined Japanese patent publicationxe2x80x9d), alcohols having a triple bond in the molecule, thioether compounds disclosed in U.S. Pat. No. 4,126,459, mercapto compounds disclosed in JP-A-1-4739, JP-A-1-159645 and JP-A-3-101728, mesoionic compounds disclosed in JP-A-4-170539, and ammonium thiocyanate.
The concentrated fixing solution of the present invention is diluted with water to a predetermined concentration when it is used. Particularly, it is diluted in the proportion of from 0.2 to 3 parts by volume of water to one part by volume of the concentrated fixing solution.
The amount added of the concentrated fixing solution is 600 ml/m2 or less, preferably 500 ml/m2 or less, per the processed amount of the photographic material.
Any known development processing method can be used in the present invention, and known development processing solutions can be used. The developing agent of the developing solution which is used in the present invention cannot be particularly limited, but it is preferred to include dihydroxybenzenes and ascorbic acid derivatives, and further, a combination of dihydroxybenzenes or ascorbic acid derivatives with 1-phenyl-3-pyrazolidones, or a combination of dihydroxybenzenes or ascorbic acid derivatives with p-aminophenols is preferred in view of the developing ability.
Specific examples of dihydroxybenzene developing agents for use in the present invention include hydroquinones, chlorohydroquinones, isopropylhydroquinones, and methyl-hydroquinones, and hydroquinones are more preferred. Examples of the ascorbic acid derivative developing agent for use in the present invention include ascorbic acid, isoascorbic acid and the salts thereof.
Specific examples of 1-phenyl-3-pyrazolidones or derivatives thereof which are used in the present invention as a developing agent include 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, and 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone. Specific examples of p-aminophenol developing agents include N-methyl-p-aminophenol, p-aminophenol, N-(xcex2-hydroxyethyl)-p-aminophenol, and N-(4-hydroxyphenyl)glycine, and N-methyl-p-aminophenol is more preferred. Dihydroxybenzene developing agents are preferably used in an amount of from 0.05 mol/liter to 0.8 mol/liter. When a combination of dihydroxybenzenes with 1-phenyl-3-pyrazolidones or with p-aminophenols is used, the former is preferably used in an amount of from 0.05 mol/liter to 0.5 mol/liter, and the latter is preferably used in an amount of 0.06 mol/liter or less.
Representative examples of the preservative which are used in the present invention include sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, potassium methabisulfite, and sodium formaldehyde bisulfite. Sulfite is used in an amount of 0.20 mol/liter or more, preferably 0.3 mol/liter or more, but, when the preservative is added in an excessive amount, it is settled in a developing solution and causes a contamination of the solution. The upper limit of the added amount is, therefore, preferably 1.2 mol/liter. Examples of alkali agent for adjusting a pH include a conventional water-soluble inorganic alkali metal salt (e.g., sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate). Additives which can be used in addition to the above include a development inhibitor (e.g., sodium bromide, potassium bromide); an organic solvent (e.g., ethylene glycol, diethylene glycol, triethylene glycol, dimethylformamide); a development accelerator (e.g., alkanolamines such as diethanolamine and triethanolamine, imidazole or derivatives thereof); an antifoggant or a black pepper inhibitor (e.g., mercapto compounds such as 1-phenyl-5-mercaptotetrazole, indazole compounds such as 5-nitroindazole, benzotriazole compound). Further, if necessary, a color adjustor, a surfactant, a defoaming agent, a water softening agent, and a hardening agent may be contained. In addition to the above, compounds disclosed in JP-A-62-212651 as a development streak inhibitor and compounds disclosed in JP-A-61-267759 as a dissolution aid may be used.
The developing solution which is used in the present invention may include, as a buffer, a boric acid disclosed in JP-A-62-186259, saccharides (e.g., saccharose) disclosed in JP-A-60-93433, oximes (e.g., acetoxime), phenols (e.g., 5-sulfosalicylic acid), or tertiary phosphates (e.g., sodium salt, potassium salt).
Processing solutions are desired to be concentrated with a view to reducing transportation costs, waste package materials and spaces, and to be diluted when they are used.
It is effective for concentrating a developing solution that a salt component contained in the developing solution is converted to a potassium salt. The photographic material is subjected to washing or stabilizing processing after being development processed and fixing processed. Washing or stabilizing processing can be carried out with a replenishing amount of 3 liters or less per m2 of the silver halide photographic material (including zero, i.e., washing by water in a reservoir). That is, not only water saving treatment is possible, but also piping for installation of an automatic processor is not necessary. When washing is carried out with a small amount of water, it is preferred to use a washing tank equipped with a squeegee roller or a crossover roller disclosed in JP-A-63-18350 and JP-A-62-287252. The addition of various kinds of oxidizing agents and the provision of filters for filtration may be combined to reduce environmental pollution which becomes a problem when washing is carried out with a small amount of water. Further, all or a part of the overflow generated from the washing tank or the stabilizing tank by the replenishment of water applied with an antimold means, in proportion to the progress of the processing, can be utilized in the preceding processing step, i.e., a processing solution having a fixing ability as disclosed in JP-A-60-235133. Moreover, a water-soluble surfactant or a defoaming agent may be included in washing water to prevent generation of foam streaks which is liable to generate when washing is conducted with a small amount of water and/or to prevent components of the processing agents adhered to a squeegee roller from transferring to the processed film. In addition, dye adsorbents disclosed in JP-A-63-163456 may be included in a washing tank to inhibit contamination by dyes dissolved from the photographic material.
Further, there is a case where the photographic material is subjected to a stabilizing processing after a washing processing. Examples thereof include a bath containing compounds disclosed in JP-A-2-201357, JP-A-2-132435, JP-A-1-102553 and JP-A-46-44446 used as a final bath. This stabilizing bath may contain, if necessary, ammonium compounds, metal compounds such as Bi and Al, brightening agents, various kinds of chelating agents, pH adjusting agents, hardening agents, sterilizers, antimold agents, alkanolamines, and surfactants. Tap water, deionized water, and water sterilized by a halogen or ultraviolet sterilizing lamp, or by various oxidizing agents (e.g., ozone, hydrogen peroxide, chlorate) are preferably used as washing water in a washing step or a stabilizing step. The developing and fixing time of the development processing of the present invention is 40 seconds or less, and preferably from 6 seconds to 35 seconds, and the temperature of each solution is preferably from 25xc2x0 C. to 50xc2x0 C., and more preferably from 30xc2x0 C. to 40xc2x0 C. The temperature and the time of the washing or stabilizing bath are more preferably from 0 to 50xc2x0 C. and 40 seconds or less. According to the present invention, the photographic material which has been developed, fixed and washed (or stabilized) is dried after the washing water of which has been squeezed by means of a squeegee roller. Drying is carried out at a temperature of from 40xc2x0 C. to 100xc2x0 C., and the drying time is varied optionally depending on circumstances.
Examples of the silver halide of the silver halide emulsion which is used in the photographic material of the present invention include conventional silver halide emulsions comprising, for example, silver bromide, silver iodobromide, silver chloride, silver chlorobromide, and silver chloroiodobromide, and preferably silver chlorobromide containing 60 mol % or more of silver chloride as a negative type silver halide emulsion, or silver chlorobromide, silver bromide, and silver iodobromide containing 60 mol % or more of silver bromide as a positive type silver halide emulsion. The silver halide grains can be prepared by any of an acidic method, a neutral method and an ammoniacal method. The silver halide grains may be those having uniform distribution of silver halide composition within the grains or may be core/shell type grains in which the silver halide compositions are different between the interior and the surface, or may be either grains in which the latent image is mainly formed on the grain surfaces, or grains in which the latent image is mainly formed within the grains. The shape of the silver halide grains for use in the present invention may be any shape, and one preferred example is a cubic having a {100} phase as a crystal surface. Further, grains having an octahedral form, a tetradecahedral form or a dodecahedral form may be prepared and used according to the methods disclosed in, for example, U.S. Pat. Nos. 4,183,756, 4,225,666, JP-A-55-26589, JP-B-55-42737, and The Journal of Photographic Science, 21-39 (1973). Grains having twin crystal phases may also be used. The form of the silver halide grains according to the present invention may be uniform, or mixtures of various forms may be used. A monodispersed emulsion is preferably used in the present invention. As monodispersed silver halide grains in the monodispersed emulsion, silver halide grains in which the weight of the silver halide grains included in xc2x110% of the average grain diameter is 60% or more of the total silver halide grains are preferred.
Various metal ions can be introduced into the interior and/or the surface of the silver halide grains for use in the emulsion of the present invention during formation of the grains or during ripening of the grains by using cadmium salts, zinc salts, lead salts, thallium salts, iridium salts and complex salts thereof, rhodium salts and complex salts thereof, iron salts and complex salts thereof. The photographic emulsions for use in the present invention may be subjected to reduction sensitization using a reducing substance or noble metal sensitization using a noble metal compound in addition to sulfur sensitization or gold-sulfur sensitization. The above emulsion may be used alone or two or more kinds may be mixed as light-sensitive emulsions. After completion of the above described chemical sensitization, various stabilizers can be used in the present invention, for example, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 5-mercapto-1-phenyltetrazole, and 2-mercaptobenzothiazole. Further, a silver halide solvent such as thioether, and a crystal habit controlling agent such as a mercapto group-containing compound or a sensitizing dye may be used, if necessary. When a so-called hard gradation agent such as a tetrazolium compound, a hydrazine compound or a polyalkylene oxide compound is added to a photographic material, especially a photographic material for printing, in the present invention, preferable effects can be obtained.
The photographic emulsion of the silver halide photographic material of the present invention may be spectrally sensitized using a sensitizing dye to a relatively long wavelength blue light, green light, red light and infrared light. Examples of the dyes used for this sensitization include a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a hemicyanine dye, a styryl dye, and a hemioxonol dye. They may be used alone or in combination. A combination of the sensitizing dyes is often used for the purpose of super-sensitization. The hydrophilic colloid layer of the silver halide photographic material of the present invention may contain water-soluble dyes as a filter dye or for the purpose of preventing irradiation, halation, or for various other purposes. Examples of these dyes include an oxonol dye, a hemioxonol dye, a styryl dye, a merocyanine dye, a cyanine dye and an azo dye. Among these, an oxonol dye, a hemioxonol dye and a merocyanine dye are preferred. Specific examples thereof are described in West German Patent No. 616,007, British Patent Nos. 584,609, 1,117,429, JP-B-26-7777, JP-B-39-22069, JP-B-54-38129, JP-A-48-85130, JP-A-49-99620, JP-A-49-114420, JP-A-49-129537, PB Report No. 74175, and Photographic Abstract, 128 (""21). These dyes are especially preferred to be used in illuminated room dot-to-dot work photographic materials. A solid fine grain dispersion of a dye disclosed in Japanese Patent No. Application No. 5-244717, pp. 23-30 may also be used. When dyes or UV absorbers are contained in the hydrophilic colloid layer of the silver halide photographic material of the present invention, they may be mordanted with, for example, a cationic polymer.
Various compounds can be added to the above photographic emulsion for preventing lowering of sensitivity and generation of fog during production, storage or processing of the silver halide photographic material. A technique to improve dimensional stability by including a polymer latex in the silver halide emulsion layer or the backing layer can also be used. These techniques are disclosed in, for example, JP-B-39-4272, JP-B-39-17702, and JP-B-43-13482. Gelatin is used as a binder in the photographic material of the present invention, but gelatin derivatives, cellulose derivatives, a graft polymer of gelatin with other polymers, other proteins, sugar derivatives, cellulose derivatives, and hydrophilic colloids of synthetic hydrophilic polymers such as homopolymers or copolymers can be used in combination.
The photographic material of the present invention can further contain various kinds of additives according to purposes. They are described in detail in the Research Disclosure, Vol. 176, Item 17643 (December, 1978) and ibid., Vol. 187, Item 18716 (November, 1979), and the locations are shown in the following table.
Examples of the support for use in the photographic material of the present invention includes paper laminated with, for example, xcex1-olefin polymers (e.g., polyethylene, polypropylene, ethylene/butene copolymer), a flexible reflective support (e.g., synthetic paper), a film of semi-synthetic or synthetic polymers (e.g., cellulose acetate, cellulose nitrate, polystyrene, polyvinyl chloride, poly-ethylene terephthalate, polycarbonate, polyamide), a flexible support having provided a reflective layer on the above-described film, and metals, and polyethylene terephthalate is more preferred. Examples of the underlayer which can be used in the present invention include an underlayer treated with organic solvents containing polyhydroxybenzenes disclosed in JP-A-49-3972, and an underlayer treated with water latex disclosed in JP-A-49-11118 and JP-A-52-104913.
The surface of these underlayers may be treated chemically or physically. Such a treatment includes, for example, a surface activation treatment such as a chemical treatment, a mechanical treatment, and a corona discharge treatment. The present invention can be applied to various photographic materials for, for example, printing, X-ray, general negative type, general reversal type, general positive type, direct positive type.
It is preferred that the processing solutions for use in the present invention are preserved in a package material having low oxygen transmission disclosed in JP-A-61-73147. When the replenishing amounts of the processing solutions are reduced, it is preferred to make the contact area of the processing solution with air in the processing tank small to prevent evaporation of the solution or air oxidation. Automatic developing machines of the roller transport type are disclosed in U.S. Pat. Nos. 3,025,779 and 3,545,971, which are merely referred to as roller transport type processors in the present invention. These roller transport type processors comprise four steps of developing, fixing, washing and drying. It is most preferred for the processing of the present invention to follow in these four steps, although other steps (e.g., a stopping step) are not excluded.